Genotypic and phenotypic characteristics of Yersinia spp. isolates from food and man Original Research Article

Yersinia strains collected by the Unit of Enteric Pathogens of the Istituto Superiore di Sanità were analysed for bioserogroup, virulence-related characteristics, DNA plasmid profile and biotype. The isolates were from clinical and food samples, 26 were Y. enterocolitica, four Y. intermedia and four Y. frederiksenii. Seventeen were isolated in Northern Italy, 11 in Southern Italy, five in Central Italy and one from a sample of mussels imported from Greece. Virulence-related characteristics were expressed only by four Y. enterocolitica, bioserogroup 4:O3 associated with the presence of a plasmid weighing 76·8 Kbp. The DNA digested by Spe I and Xba I and analysed by PFGE generated restriction patterns of 12–23 bands, ranging between 400 and 20 Kbp. The similarities of the DNA fingerprintings ofY. enterocolitica strains generated using Spe I and Xba I and calculated by Diceʹs index were not closely related to bioserogroup.